>OK, I understand where you're coming from. I changed my Nissan
>over to one of the new organic acid type coolants (nitrite,
>phosphate, borate and silicate free) over 12 months ago. But I
>did a very thorough flush with demineralised water first.
You need to use the correct coolant. Since dealers usually only charge
a couple dollars more than the discounts houses for it, it often makes
sense to use the factory recommenced coolant and avoid the learning
curve. It's not worth going "long life" with a coolant the
manufacturer didn't recommend.
That said, if you want to know more... Prestone developed the first
anti-corrosion additives for coolant 40 years ago. They used
silicates. Prestone green is a high-silicate formula.
There are a variety of other coolants on the market using new
technologies.
The "Long Life" coolants are generally carboxyilic based like Dexcool.
No phosphates, no silicates, but big problems. You should NOT use
these coolants as they have serious "contamination" issues. Google GM
and Dexcool for more info - find cars with corrosion problems at 16K
miles. Dexcool requires an incredibly clean starting point and
contaminants cause them to cause corrosion. Contaminants known to
cause problems include factory sealer, solder, and believe it or not,
*air*. Using this in a car that had other coolants previously is not
smart.
It's told that some folks (Valvoline is one) have developed a *long
life* carbooxy without the contamination issues that plagued Dexcool.
I'm wary, even though I like the guys in the Valvoline research
department. (FYI - Valvoline OEM's a lot of coolant for other
companies and the drums you see in the garages & dealers).
The other new coolants use a similar carbooxylic base but are not the
long life type like Dex. Valvoline markets these as G-48 and G-05.
They are in use by Ford, Damilier/Chrysler and some Euro cars. They
have a LOW silicate but higher phosphate design. Not bad for your
Nissan but not ideal.
Lastly there are NO silicate coolants from Japanese manufacturers. As
far as I know, there are no commercial (non dealer) equivalents to
these. Nissan recommends a NO silicate formula. Japanese cars are know
to wear water pumps early and silicates are the perceived cause.
Despite another 10lbs of research I've done into this, I've decided
the it's not worth the time to keep up any more. I just go to the
dealer, spend a couple extra bucks, and get the factory coolant. All
done, and I sleep and night.
John Henderson - 09 Jul 2007 22:04 GMT
> You need to use the correct coolant. Since dealers usually
> only charge a couple dollars more than the discounts houses
[quoted text clipped - 19 lines]
> factory sealer, solder, and believe it or not, *air*. Using
> this in a car that had other coolants previously is not smart.
Thank you for your concern - all of which is well worth saying
in this forum for the benefit of others.
I also did my research well, and found a reasonable consensus
(among those who should know) roughly in agreement with your
assessment.
> It's told that some folks (Valvoline is one) have developed a
> *long life* carbooxy without the contamination issues that
[quoted text clipped - 8 lines]
> some Euro cars. They have a LOW silicate but higher phosphate
> design. Not bad for your Nissan but not ideal.
Except no phosphate is used in the Euro formulations of these
"hybrid" coolants. They're generally low-silicate, free of
phosphate and nitrite, but with benzoic acid. Because I'm more
conservative with other peoples' property than my own, I use
one of these (Motul "Inugel Expert") in the older family cars
which I service but do not own myself.
Higher-phosphate is a largely a Japanese compromise, and one
which I do not feel entirely at ease with.
> Lastly there are NO silicate coolants from Japanese
> manufacturers. As far as I know, there are no commercial (non
[quoted text clipped - 6 lines]
> just go to the dealer, spend a couple extra bucks, and get the
> factory coolant. All done, and I sleep and night.
As I mentioned, I decided to switch my own Nissan over to a full
OAT coolant. Since I had already switched my VW over to VW
G12+ coolant (mixes with many silicate-based coolants without
problems), that's what I now use in the Nissan too. Given that
G12+ is now the recommended coolant for old engines like
pre-VAG (VW automotive group) Skodas, Audis, Seats and so on, I
am more than happy to do the experiment.
John